U.S. patent application number 10/677251 was filed with the patent office on 2004-04-22 for method and apparatus for patterning an organic electroluminescence device.
This patent application is currently assigned to PIONEER CORPORATION. Invention is credited to Hirasawa, Akira, Miyadera, Toshiyuki.
Application Number | 20040077250 10/677251 |
Document ID | / |
Family ID | 32089164 |
Filed Date | 2004-04-22 |
United States Patent
Application |
20040077250 |
Kind Code |
A1 |
Miyadera, Toshiyuki ; et
al. |
April 22, 2004 |
Method and apparatus for patterning an organic electroluminescence
device
Abstract
Irradiating an organic electroluminescence device with a laser
beam to form a luminescent pattern on the organic
electroluminescence device. According to the configuration, the
forming of the luminescent pattern of the organic
electroluminescence device can be achieved at high efficiency and
with low cost.
Inventors: |
Miyadera, Toshiyuki;
(Saitama, JP) ; Hirasawa, Akira; (Saitama,
JP) |
Correspondence
Address: |
MORGAN LEWIS & BOCKIUS LLP
1111 PENNSYLVANIA AVENUE NW
WASHINGTON
DC
20004
US
|
Assignee: |
PIONEER CORPORATION
|
Family ID: |
32089164 |
Appl. No.: |
10/677251 |
Filed: |
October 3, 2003 |
Current U.S.
Class: |
445/24 |
Current CPC
Class: |
H01L 51/0015 20130101;
H01L 51/0078 20130101; H01L 51/0081 20130101; H01L 27/3239
20130101; H01L 51/0014 20130101; H01L 51/0059 20130101 |
Class at
Publication: |
445/024 |
International
Class: |
H01J 009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 4, 2002 |
JP |
P2002-292021 |
Claims
What is claimed is:
1. A method of patterning an organic electroluminescence device,
the method comprising irradiating an organic electroluminescence
device with a laser beam to form a luminescent pattern thereon.
2. The method as claimed in claim 1, wherein the laser beam
comprises a laser beam of a blue emission wavelength.
3. A method of producing an organic electroluminescence device, the
method comprising: forming a first electrode on a substrate;
forming an organic electroluminescence layer on the first
electrode; forming a second electrode on the organic
electroluminescence layer; sealing the first electrode, the organic
electroluminescence layer and the second electrode to produce an
organic luminescence device having a substantially uniform light
emission characteristic; and irradiating the organic luminescence
device with a laser beam to form a predetermined luminescent
pattern thereon.
4. The method as claimed in claim 3, wherein the laser beam
comprises a laser beam of a blue emission wavelength.
5. An apparatus for patterning an organic electroluminescence
device comprising a laser irradiation section configured to
irradiate an organic electroluminescence device with a laser beam
to form a luminescent pattern thereon.
6. The apparatus as claimed in claim 5, wherein the laser
irradiation section comprises a semiconductor laser configured to
output a laser beam of a blue emission wavelength.
7. The apparatus as claimed in claim 5 further comprising: a
storage section configured to store a predetermined pattern; and a
control section configured to control the laser irradiation section
to irradiate the organic electroluminescence device with the laser
beam in accordance with the predetermined pattern.
8. The apparatus as claimed in claim 5, wherein the laser
irradiation section further comprises: a light source configured to
emit the laser beam; and a scanning section configured to scan the
organic electroluminescence device with the laser beam emitted from
the light source.
9. The apparatus as claimed in claim 8, wherein the scanning
section comprises a polygon mirror.
10. The apparatus as claimed in claim 7 further comprising a
pattern input section configured to input data and store the data
in the storage section as the predetermined pattern.
11. The apparatus claimed in claim 10, wherein the pattern input
section comprises a data input section configured to be operable by
a user to input the data.
12. The apparatus claimed in claim 10, wherein the pattern input
section comprises an image scanning section configured to scan an
image as the data.
13. The apparatus claimed in claim 10, wherein the pattern input
section comprises an eternal-storage section configured to read out
data recorded on a recording medium as the data.
Description
[0001] The present disclosure relates to the subject matter
contained in Japanese Patent Application No. 2002-292021 filed on
Oct. 4, 2002, which is incorporated herein by reference in its
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method and apparatus for
patterning an organic electroluminescence device, and a method of
producing an organic electroluminescence device.
[0004] 2. Description of the Related Art
[0005] As a thin luminescent device, there is known an organic
electroluminescence device (Hereinafter, referred to simply as
"organic EL device"). An organic EL device includes a substrate, an
anode formed on the substrate, an organic EL layer configured by a
plurality of layers stacked on the anode electrode, and a cathode
formed on the organic EL layer. The organic EL layer is a layer
made of organic material and having at least a luminescent
layer.
[0006] When a voltage is applied between the anode and the cathode,
holes and electrons are injected from the anode and cathode,
respectively, into the luminescent layer. The holes and electrons
recombine in the luminescent layer to form excitons. The excitons
drop to a lower energy level during a very short time period, and a
differential energy of part of the excitons between the lower
energy level and the excited state is emitted in the form of light.
The light emitted in the luminescent layer exits toward the
substrate side or the cathode side. As a result, the organic EL
device performs as a luminescent device.
[0007] When the luminescent pattern of the organic EL device is to
have an arbitrary shape, it may be contemplated to employ a
technique in which one of members constituting the element,
including the electrodes, the luminescent layer, and an insulating
layer is formed into a desired shape.
[0008] FIG. 7 is a section view of an organic EL device 100 in
which a luminescent pattern is formed. In the organic EL device
100, an anode 120 is first grown on a substrate 110 by the vapor
deposition method, the sputtering method, or the like. Then, an
insulating layer 130 is patterned on the anode 120 by the
photolithography method or the like. The pattern formation in
forming the insulating layer 130 is performed so that a portion
from which light is not to be emitted is covered by the insulating
layer 130. Thereafter, an organic EL layer 140 and a cathode 150
are sequentially formed on the anode 120 or the insulating layer
130. As a result, the organic EL device having a desired
luminescent pattern is obtained.
[0009] FIG. 8 is a section view of an organic EL device 200 in
which a luminescent pattern is formed. In the organic EL device
200, an anode 220 having a desired shape is formed on a substrate
210 by the etching method or the like. An organic EL layer 230 and
a cathode 240 are sequentially formed on the substrate 210 and the
anode 220, thereby obtaining the organic EL device having a desired
luminescent pattern.
[0010] Another method of forming a luminescent pattern into an
arbitrary shape is a method in which a plurality of luminescent
elements is arranged in a matrix in a luminescent region. The
luminescent elements are configured to emit light independently and
only required elements are driven, thereby obtaining a desired
luminescent pattern.
[0011] In manufacturing the organic EL device 100 or 200, however,
the internal structure of the element must be designed for each of
luminescent patterns. Therefore, a long time period and much labor
are required to obtain an organic EL device having a desired
luminescent pattern. As a result, the manufacturing cost of such an
organic EL device is increased, and such an organic EL device is
not suitable for high-mix low-volume manufacturing.
[0012] In the method in which a plurality of luminescent elements
arranged in a matrix is formed in a luminescent region, a voltage
must be selectively supplied to each of the luminescent elements,
and the circuit configuration is therefore become complicated.
[0013] In order to form areas of different luminescent brightness
in a luminescent region, components such as a driving circuit and a
power source must be configured so as to correspond to each of the
luminescent brightness. Therefore, the system becomes complicated,
and the resulting luminescent element tends to become high in
cost.
[0014] As an example of a display device which is provided with a
plurality of luminescent regions of different luminescent
brightness without conducting a brightness adjustment from the
outside is disclosed in a Japanese Patent publication
JP-A-2001-167881 (specifically, on page from 2 to 3 and in FIG.
2).
[0015] According to the publication, a desired luminescent pattern
is obtained by irradiating an organic EL device with UV light to
modify or break the light-emitting capability. According to the
method, a desired luminescent pattern is obtained without
conducting a process of placing an insulating layer in the organic
EL device, or shaping an electrode. Therefore, the production steps
can be simplified.
[0016] However, in the method described in the publication, the
whole device is irradiated with UV light. In order to obtain a
desired luminescent pattern, therefore, the UV irradiation must be
conducted after a region not to be irradiated or a luminescent
region is masked with a masking member. Therefore, in the method
described in the publication, a mask must be previously produced
for each of luminescent patterns, and hence the production steps
become complicated. Since a mask must be produced for each of
luminescent patterns, the manufacturing efficiency is poor, and the
manufacturing cost becomes increased. Consequently, the method is
not suitable for high-mix low-volume manufacturing.
SUMMARY OF THE INVENTION
[0017] It is therefore an object of the invention to provide an
organic EL device having a luminescent pattern formed at high
efficiency and with low cost.
[0018] In order to achieve the object of the invention, according
to a first aspect of the invention, there is provided a method of
patterning an organic electroluminescence device, the method
including irradiating an organic electroluminescence device with a
laser beam to form a luminescent pattern thereon.
[0019] According to a second aspect of the invention, there is
provided a method of producing an organic electroluminescence
device, the method including: forming a first electrode on a
substrate; forming an organic electroluminescence layer on the
first electrode; forming a second electrode on the organic
electroluminescence layer; sealing the first electrode, the organic
electroluminescence layer and the second electrode to produce an
organic luminescence device having a substantially uniform light
emission characteristic; and irradiating the organic luminescence
device with a laser beam to form a predetermined luminescent
pattern thereon.
[0020] According to a third aspect of the invention, there is
provided an apparatus for patterning an organic electroluminescence
device including a laser irradiation section configured to
irradiate an organic electroluminescence device with a laser beam
to form a luminescent pattern thereon.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The above objects and advantages of the present invention
will become more apparent by describing in detail a preferred
exemplary embodiment thereof with reference to the accompanying
drawings, wherein:
[0022] FIG. 1 is a diagram showing an apparatus for patterning an
organic EL device according to an embodiment of the invention;
[0023] FIG. 2 is a section view showing the structure of the
organic EL device;
[0024] FIG. 3 is a diagram showing in detail the structure of a
laser irradiation section;
[0025] FIG. 4 is a view showing the manner of irradiating the
organic EL device with a laser beam;
[0026] FIG. 5 is a flowchart showing a procedure of patterning the
organic EL device by using the patterning apparatus;
[0027] FIG. 6 is an exploded perspective view of the organic EL
device after the laser beam irradiation;
[0028] FIG. 7 is a section view of a conventional organic EL device
in which a luminescent pattern is formed; and
[0029] FIG. 8 is a section view of another conventional organic EL
device in which a luminescent pattern is formed.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0030] Referring now to the accompanying drawings, there are shown
a preferred embodiment of the invention.
[0031] FIG. 1 is a diagram showing an apparatus for patterning an
organic electroluminescence device (Hereinafter, referred to simply
as "organic EL device") according to an embodiment of the
invention. The patterning apparatus 1 irradiates an organic EL
device 10 with a laser beam to form a predetermined luminescent
pattern on the organic EL device 10.
[0032] FIG. 2 is a section view showing the structure of the
organic EL device 10 to be irradiated with a laser beam. The
organic EL device 10 includes: a substrate 11 configured by a
transparent material such as glass; an anode 12 formed on the
substrate 11; an organic EL layer 13 configured by a plurality of
layers stacked on the anode 12; and a cathode 14 formed on the
organic EL layer 13. The organic EL layer 13 is a layer made of
organic material having at least a luminescent layer.
[0033] The organic function layer 13 has a hole-injecting layer
13a, a hole-transporting layer 13b, a luminescent layer 13c and an
electron-injecting layer 13d which are sequentially stacked with
starting from the side of the anode 12. When a voltage is applied,
the hole-injecting layer 13a injects holes into the luminescent
layer 13c via the hole-transporting layer 13b, and the
electron-injecting layer 13d injects electrons into the luminescent
layer 13c. In the luminescent layer 13c, the holes and the
electrons recombine to form excitons. The excitons drop to a lower
energy level during a very short time period, and a differential
energy of part of the excitons between the lower energy level and
the excited state is emitted in the form of light. The light
emitted in the luminescent layer 13c exits toward the side of the
substrate 11 or the side of the cathode 14. As a result, the
organic EL device 10 performs as a luminescent element.
[0034] The organic EL device 10 is produced by growing the anode 12
on the substrate 11, sequentially growing organic EL layers 13a to
13d on the anode 12, and then growing the cathode 14. After the
growth of the cathode 14, a seal layer 15 for sealing the element
is grown. The organic EL device 10 is configured to have no
particular luminescent pattern, and has a substantially uniform
brightness distribution.
[0035] The patterning apparatus 1 includes: a laser irradiation
section 2 which irradiates the organic EL device 10 with a laser
beam; a control section 3; a storage section 4; a data input
section 5; a scanner section 6; an external-storage medium read
section 7; and an organic EL device fixation section 8.
[0036] FIG. 3 is a diagram showing in detail the structure of the
laser irradiation section 2. The laser irradiation section 2 has a
light source 21, a cylindrical lens 22, a polygon mirror 23, a
motor 24, an f.theta. lens 25.
[0037] The light source 21 is a semiconductor laser that emits a
laser beam of a predetermined wavelength. The laser beam impinges
on the organic EL device 10. In the organic EL layer 13 of the
organic EL device 10, the resistance of an irradiated portion is
increased in accordance with the amount of irradiation of the laser
beam, so that the luminescent brightness is reduced or the
irradiated portion is not luminescent. In accordance with a control
signal from the control section 3, the light source 21 turns ON/OFF
the emission of the laser beam. The light source 21 is configured
so that the laser beam intensity can be changed in plural steps in
accordance with another control signal from the control section
3.
[0038] The laser beam emitted from the light source 21 may have any
wavelength as far as the resistance of the organic EL layer can be
increased by modification or breakage. Particularly, a laser beam
of a blue emission wavelength (420 nm or shorter, more preferably
380 nm or shorter) is preferably used because of its high beam
energy.
[0039] The cylindrical lens 22 converts the laser beam emitted from
the light source, into parallel light. The parallel light obtained
as a result of the conversion by the cylindrical lens 22 is
inputted to the polygon mirror 23.
[0040] The polygon mirror 23 is a hexagonal prism shaped mirror in
which a mirror surface is formed on each of the six side faces. The
polygon mirror 23 is driven by the motor 24 to be rotated at high
speed. The laser beam is reflected by the mirror surfaces
respectively formed on the side faces. The incident angle of the
laser beam to each of the mirror surfaces is continuously changed
in accordance with the rotation of the polygon mirror 23, and hence
the emission direction of the reflected laser beam is continuously
changed according to the angle. As a result, the laser beam scans
the organic EL device 10 in one direction in accordance with the
change of the emission angle. The laser beam reflected by the
polygon mirror 23 is sent to the f.theta. lens 25.
[0041] The motor 24 rotates the polygon mirror 23 in accordance
with a control signal from the control section 3.
[0042] The f.theta. lens 25 is a focal lens by which the laser beam
reflected from the polygon mirror 23 is constricted so as to be
focused on the organic EL device. The f.theta. lens 25 has an
aspheric emission surface, and is configured so that the laser beam
is focused on the organic EL device 10 irrespective of the incident
angle to the f.theta. lens 25. On the other hand, the organic EL
device 10 is placed at a position where the laser beam is focused
by the f.theta. lens 25.
[0043] The storage section 4 is configured by a volatile RAM
memory, a nonvolatile hard disk drive, and the like, and stores
various data. In accordance with instructions from the control
section 3, the storage section 4 stores various data, and reads out
data stored in the control section 3. The storage section 4 stores
various programs to be implemented by the control section 3.
[0044] The data input section 5 is configured by input devices such
as a mouse and a keyboard, and a display device. The user operates
the input devices such as the mouse and the keyboard to input a
luminescent pattern of the organic EL device. The data input
section 5 is configured so that predetermined luminescent patterns
stored in the storage section 4 are displayed on the display
device, thereby enabling the user to select the luminescent pattern
which is to be formed on the organic EL device, by using the mouse
and the keyboard. The input or selected luminescent pattern is
stored into the storage section 4.
[0045] The scanner section 6 is an image read section configured
by: a scanner which reads an image recorded on a sheet or the like
to convert the image into digital data; a digital camera which
takes an image of an object to convert the image into digital data;
and other devices. The digital data which is obtained by the
scanner section 6 is stored as luminescent pattern data into the
storage section 4.
[0046] The external-storage medium read section 7 is an
external-storage section which reads an image, text data, and the
like stored on a storage medium. The read data is stored as
luminescent pattern data into the storage section 4. The
external-storage medium read section 7 is configured by an optical
disk reading apparatus such as a CD-ROM drive or a DVD-ROM drive, a
magnetic disk reading apparatus such as a floppy disk drive, a
magnet-optical disk reading apparatus such as an MO drive, and the
like.
[0047] The organic EL device fixation section 8 is used for fixing
the organic EL device 10 which is to be irradiated with a laser
beam, and has fixing projections 8a for fixing the organic EL
device 10 onto the organic EL device fixation section 8. In
accordance with a control signal from the control section 3, the
organic EL device fixation section 8 moves in a direction
perpendicular to the scanning direction of the laser beam. The
organic EL device fixation section 8 is transparent. The laser beam
emitted from the laser irradiation section 2 is transmitted through
the organic EL device fixation section 8 and then enters the inside
of the organic EL device 10 through the transparent electrode
12.
[0048] Hereinafter, the patterning of an organic EL device by using
the patterning apparatus 1 of the embodiment will be described with
reference to FIGS. 4 and 5.
[0049] FIG. 5 is a flowchart showing the procedure of patterning
the organic EL device 10 by using the patterning apparatus 1.
First, the organic EL device 10 is prepared in the following
manner. The anode 12 is grown on the substrate 11, the organic EL
layers 13a to 13d are sequentially grown on the anode 12, and the
cathode 14 is then grown. After the cathode 14 is grown, the seal
layer 15 for sealing the element is grown. The organic EL device 10
is configured to have no particular luminescent pattern, and has a
brightness distribution substantially uniform over the whole
surface. The organic EL device 10 is not required to be produced
for each patterning process. A predetermined number of organic EL
devices may be previously produced and stocked. In the example, the
organic EL devices are used in which ITO, Cu_PC, NPB, Alq.sub.3,
Li.sub.2O and A1 are sequentially stacked on a glass substrate and
the layers are sealed by an SiN layer.
[0050] Next, the organic EL device which is to be subjected to the
patterning process is placed on the organic EL device fixation
section 8 (step S1), and various settings of the patterning process
are conducted. The patterning apparatus 1 first reads data from one
of the data input section 5, the scanner section 6, and the
external-storage medium read section 7 (step S2). The read data is
temporarily stored into the storage section 4 via the control
section 3.
[0051] Next, the control section 3 checks the data format of the
read data, and determines whether the data format is one for
patterning or not (step S3). If the data format of the read data is
one for patterning, the control proceeds to step S5.
[0052] If the data format of the read data is not one for
patterning, a program for converting the data format is read out
from the storage section 4, and then activated to convert the data
format into one for patterning (step S4). Specifically, processes
such as those of changing the pixel number of image data to a
predetermined number, and converting the number of gradations of
each pixel into a predetermined number are performed.
[0053] On the basis of the read data, the control section 3 then
determines a scanning pattern by which the organic EL device 10 is
scanned with a laser beam (step S5). Specifically, the control
section calculates emission intensities of the laser beam at
positions on the organic EL device respectively corresponding to
the pixels of the image data. The control section 3 outputs a
control signal corresponding to the scanning pattern to drive the
motor 24, thereby rotating the polygon mirror 23. At the same time,
the control section 3 outputs a control signal corresponding to the
scanning pattern to drive the light source 21 in synchronization
with the rotation of the polygon mirror, thereby causing the laser
beam to be emitted. The control section 3 supplies a control signal
synchronized with the rotation of the polygon mirror, to the
organic EL device fixation section 8 to move the organic EL device
Fixation section 8 in a direction perpendicular to the scanning
direction (the direction of the arrow A shown in FIG. 4) of the
laser beam. As a result, the control section 3 performs the control
operation so that the organic EL device 10 is irradiated with the
laser beam in accordance with the scanning pattern and the
predetermined luminescent pattern is formed on the organic EL
device (step S6).
[0054] FIG. 4 shows the manner of irradiating the organic EL device
10 fixed onto the organic EL device fixation section 8 with the
laser beam. In FIG. 4, the blank portions show areas, which are not
irradiated with the laser beam, and the hatched portion shows an
area which is irradiated with the laser beam.
[0055] The laser irradiation section 2 scans the organic EL device
in the direction of the arrow A to irradiate the organic EL device
with the laser beam of the emission intensity corresponding to the
scanning pattern. In accordance with instructions from the control
section 3, the organic EL device fixation section 8 moves in a
direction perpendicular to the scanning direction (the direction of
the arrow A) of the laser beam. As a result, the laser irradiation
section 2 irradiates the whole surface of the organic EL device
with the laser beam of the emission intensity corresponding to the
scanning pattern.
[0056] FIG. 6 is an exploded perspective view of the organic EL
device 10 after the laser beam irradiation. In the organic EL
device 10 of FIG. 6, the blank portions show the areas that are not
irradiated with the laser beam, and the hatched portion shows the
area which is irradiated with the laser beam, and in which the
resistance is increased. When the laser beam irradiation is
performed in the way described above, the resistance of the organic
EL layer 13 is increased, and the luminescence intensities of the
irradiated portions are lowered. When a voltage is applied between
the electrodes 12 and 14, therefore, the portion which was not
irradiated with the laser beam emits intense light, so that
characters such as "AB" are formed on the organic EL device as
shown in FIG. 6.
[0057] According to the patterning apparatus 1 of the embodiment,
the organic EL device 10 is irradiated with a laser beam in
accordance with a predetermined pattern to form a luminescent
pattern corresponding to the predetermined pattern on the organic
EL device 10. Therefore, a luminescent pattern can be formed
without causing the organic EL device to have a special element
structure, whereby the cost for patterning the organic EL device
can be lowered. As a result, high-mix low-volume manufacturing of
an organic EL device can be easily achieved.
[0058] In the patterning apparatus of the embodiment, a laser beam
is used, and hence it is not required to prepare a supplementary
member such as a masking member. Therefore, additional process such
as those of producing a masking member and placing the masking
member on an organic EL device can be eliminated, so that an
organic EL device can be efficiently patterned. Consequently,
high-mix low-volume manufacturing of an organic EL device is
facilitated, and commercial use of an organic EL device is
expanded.
[0059] In the patterning apparatus of the embodiment, the laser
beam scanning is performed by the simple configuration in which the
compact semiconductor laser and the polygon mirror are used.
Therefore, the size and cost of the apparatus can be reduced.
[0060] In the patterning apparatus of the embodiment, since data
can be read from the data input section, the scanner section, the
external-storage medium read section, and the like, the user can
produce a luminescent pattern, and the pattern can be easily read
by the patterning apparatus.
[0061] When a system using the patterning apparatus of the
embodiment is configured, an "a la carte" panel (organic EL display
device) can be immediately produced and sold, and pattering of an
organic EL device can be commercially available.
[0062] In the embodiment, a semiconductor laser is used as the
light source. The light source is not restricted to using the
semiconductor laser, and may be configured by a device of any kind
as far as it can emit a laser beam of a predetermined wavelength to
increase the resistance of the organic EL layer. For example, a gas
laser, a solid-state excitation laser, or the like may be used.
[0063] The wavelength may be set to any value as far as it allows
the resistance of the material constituting the organic EL layer to
be increased. In a case where an organic EL device having an
organic EL layer of a material which has a strong absorption
wavelength band in the visible light region, particularly, a laser
light source of a wavelength which is in the visible light region
may be used.
[0064] In the embodiment, a polygon mirror is used for the laser
beam scanning. The section for the laser beam scanning is not
particularly restricted to this as far as it can perform the laser
beam scanning. For example, the irradiation direction of a laser
beam may be fixed, and a luminescent pattern may be formed by
moving an organic EL device.
[0065] In the embodiment, an organic EL device is scanned in
accordance with predetermined data. The present invention is not
restricted to this configuration. The user may directly operate a
laser beam irradiation apparatus so as to perform a scanning
operation, or directly move an organic EL device, whereby a
luminescent pattern is formed on the organic EL device.
[0066] In the embodiment, the laser beam irradiation is performed
from the side of the transparent electrode 12. The invention is not
restricted to this structure. In the case where the back electrode
is optically transparent, the laser beam irradiation may be
performed from the side of the back electrode. The organic EL
device fixation section 8 is transparent. Alternatively, a light
passing opening may be formed in the organic EL device fixation
section 8.
[0067] In the embodiment, the organic EL device 10 has a structure
in which the anode 12 is formed on the substrate 11. However, the
organic EL device 10 may also be structured in a layered structure
that the anode 12, the organic EL layer 13 and the cathode 14 are
disposed on the substrate 11 in opposite order to the structure
shown in FIGS. 1 and 2.
[0068] Although the present invention has been shown and described
with reference to a specific preferred embodiment, various changes
and modifications will be apparent to those skilled in the art from
the teachings herein. Such changes and modifications as are obvious
are deemed to come within the spirit, scope and contemplation of
the invention as defined in the appended claims.
* * * * *